Dexmedetomidine and ketamine simultaneous administration in tigers (Panthera tigris): pharmacokinetics and clinical effects

Current practice for the chemical immobilisation of non-domestic feline species: An online survey study

BACKGROUND

Safe chemical immobilisation of wild felids is essential for both conservational management and clinical purposes. However, little is known about drug protocols and current practice.

METHODS

This study was designed as an online survey based on a questionnaire. Descriptive/correlation statistics and analysis of proportions were used for data analysis.

RESULTS

The preferred immobilisation technique was the use of darts (37% of the respondents), while the most popular drug combination was a mixture of benzodiazepines, alpha-2 adrenoreceptor agonists and dissociative anaesthetics (27%). The inclusion of ketamine in the drug mixture was associated with a quicker anaesthetic onset, as estimated by the participants (p < 0.001). Common complications were prolonged recovery (46%), bradycardia (35%), hypoventilation (32%), hypothermia (26%) and arousal (26%). Commonly encountered problems were inappropriate equipment (39%), lack of suitable drugs (27%) and inadequate knowledge of species-specific pharmacology (29%) and physiology (24%).

LIMITATIONS

Incomplete adherence to the Checklist for Reporting Results of Internet E-Surveys is acknowledged.

CONCLUSIONS

Drug protocols including both alpha-2 adrenoreceptor agonists and dissociative anaesthetics are preferred in wild felids, and the inclusion of ketamine may be useful to achieve a quick onset. Equipment/drug availability and species-specific knowledge are potential areas of improvement to improve wild felid anaesthesia.

Assessment of a Combination of Tiletamine/Zolazepam, Ketamine, and Dexmedetomidine for Anesthesia of Swine (Sus domesticus)

This study investigated the induction of anesthesia in swine by injection of tiletamine/zolazepam and ketamine in combination with either dexmedetomidine (TKD) or xylazine (TKX). We hypothesized that TKD would accelerate anesthesia onset and prolong recovery as compared TKX in swine undergoing a noninvasive radiographic procedure. A randomized crossover experiment was performed on 6 healthy, intact, male miniature swine undergoing radiographic examination. Swine were randomly assigned to one of 2 groups: 1) 5mg/kg tiletamine/zolazepam, 2.5mg/kg ketamine, and 0.0125mg/kg dexmedetomidine (TKD) or 2) 5mg/kg tiletamine/zolazepam, 2.5mg/kg ketamine, and 2.5mg/kg xylazine (TKX). Either TKD or TKX was administered intramuscularly at 0.05mL/kg to provide anesthesia for a 45-min radiographic procedure. At 45min after drug administration, atipamezole was administered. During anesthesia, swine were monitored for duration parameters (time to sternal recumbency [onset of anesthesia], lateral recumbency, loss of palpebral reflex, return of the palpebral reflex, and return to sternal recumbency [onset of recovery]) and physiologic parameters (heart rate, %SpO₂, noninvasive blood pressure, and body temperature). Duration and physiologic parameters did not differ between groups at any time point. The results indicate TKD and TKX provide comparable general anesthesia in swine undergoing a radiographic examination.

Dexmedetomidine Effectively Sedates Asian Elephants (Elephas maximus)

Simple Summary

Sedation in standing procedures is commonly performed in elephants. To successfully and safely initiate standing in elephants, chemical restraint drugs should provide sufficient sedation with minimal complications (i.e., recumbency, significant physiologic alterations, and prolonged recovery). This study investigated the sedative effects of dexmedetomidine in Asian elephants. Results suggest dexmedetomidine 1–2 µg/kg provides effective sedation. However, we suggest a single intramuscular dexmedetomidine injection of 2 µg/kg for approximately 70 min of sedation. This is the first study to demonstrate dexmedetomidine use in Asian elephants.

Abstract

This study investigated the sedative effects of dexmedetomidine in Asian elephants. We hypothesized that 2 µg/kg dexmedetomidine would provide sufficient standing sedation. A crossover design study was performed in three Asian elephants. Each elephant was assigned to 1 of 3 treatment groups—1 (D1), 1.5 (D1.5) or 2 (D2) µg/kg dexmedetomidine (intramuscular injection, IM) with a two-week ‘washout period’ between doses. Elephants were monitored for 120 min. At 120 min (Ta), atipamezole was administered IM. Sedation and responsiveness scores were evaluated. Physiological parameters (pulse rate, respiratory rate, and %SpO₂) and clinical observations were monitored during the study and for 3 days post drug administration. D2 provided the longest sedation (approximately 70 min), compared to D1 and D1.5. After Ta, each elephant’s sedative stage lessened within 10–15 min without complications. No significant abnormal clinical observations were noted throughout and during the 3-days post study period. These data suggest that a single 2 µg/kg IM dexmedetomidine injection provides sufficient standing sedation for approximately 70 min in Asian elephants.

Comparison of two injectable anaesthetic protocols in Egyptian fruit bats (Rousettus aegyptiacus) undergoing gonadectomy

Egyptian fruit bats have gained increasing interest being a natural reservoir for emerging zoonotic viruses. Anaesthesia is often required to allow safe handling of bats. We aimed to compare the sedative and cardiopulmonary effects of two balanced anaesthetic protocols in bats undergoing gonadectomy. Group DK (n = 10) received intramuscular dexmedetomidine (40 µg/kg) and ketamine (7 mg/kg), whereas group DBM (n = 10) received intramuscular dexmedetomidine (40 µg/kg), butorphanol (0.3 mg/kg) and midazolam (0.3 mg/kg). Induction time and cardiopulmonary parameters were recorded. If anaesthetic plan was inadequate, isoflurane was titrated-to-effect. At the end of surgery venous blood gas analysis was performed and atipamezole or atipamezole-flumazenil was administered for timed and scored recovery. In DBM group heart rate and peripheral oxygen saturation were significantly higher (p = 0.001; p = 0.003 respectively), while respiratory rate was significantly lower (p = 0.001). All bats required isoflurane supplementation with no significant differences between groups. Induction and recovery times showed no significant differences. In group DK a better recovery was scored (p = 0.034). Sodium and chloride were significantly higher in DBM group (p = 0.001; p = 0.002 respectively). Both anaesthetic protocols were comparable and can be recommended for minor procedures in bats.

Hematological and Biochemical Reference Values in Healthy Captive Tigers (Panthera tigris)

The tiger (Panthera tigris) is an endangered species. The health of individuals is important and any data on hematological and biochemical blood values can provide valuable information; when combined with physical assessment. This data assists in both the diagnosis of disease and some conservation strategies. The behavior of wild tigers makes it is extremely difficult to obtain biological samples from free-living subjects, therefore, data collected from captive tigers is highly valuable. The aim of this study was to provide additional information for the values of hematological and serum biochemical parameters in healthy captive tigers. Blood samples were collected from 22 clinically healthy tigers (Panthera tigris). The following parameters were analyzed: glucose, urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), total protein (TP) and red blood cells (RBCs), hemoglobin (Hb), hematocrit (Hct) and red cell indices; such as mean cell volume (MCV), mean cell Hb (MCH), mean cell Hb concentration (MCHC), platelet (PLT) and white blood cells (WBCs). The mean hematological values in our tiger population were not significantly different when compared with the same parameters in the previously studied tiger population. The mean values of RBCs and PLT were statistically significantly higher and the mean values of Hb, PCV, MCV, MCH, MCHC, and WBC were lower than the mean values obtained in previous studies on the Amur tiger. Further investigation of captive and free-living tigers is needed to identify the normal ranges for parameters in this endangered species.